Lost Soul cards in BattleForge are cards that are able to revive themselves. They mainly focus on disruption and Crowd Control. Lost Soul cards have high attack but their health is low.
"In the circle of creation, the higest bliss for a soul is to pass back into the Peaceful Light, the one spark left of the pure harmony that was once the very universe itself. For souls to reach this state, they must completely cast aside their worldly bonds. Only then are they able to open the Gate of Ashia which marks the passing into the Peaceful Light. If they're not ready they must remain in the Wailing Lands, a desolate caricature of the world of the living, where souls cry and rage until they have truly shed all their worldy hates and fears.
But the Gate of Ashia has been locked, and the key for the Peaceful Light traded in for the Forge of Creation. Ever since, the souls have been trapped in the Wailing Lands, unable to leave, never knowing when their plight might end. The fulfillment of wishes of living, bought with eternal suffering for the dead.
Millenia passed, and the souls filled and filled the Wailing Lands, with nothing to do but hate the living for the fate they had imposed upon them. Even if the living had forgotten the price they had struck this trade for or with whom the deal had been done. But destroying the Forge would not unlock the Gate of Ashia. The only hope in relief lies in either winning back the key to the gate or in ending the creation, freeing all souls and granting everyone a second chance when the world will be made anew."